JPH0721338A - Liquid drip counter - Google Patents

Abstract

PURPOSE:To provide an inexpensive liquid drip counter which can count exactly the number of drips a liquid drip irrespective of the kind of a liquid. CONSTITUTION:In a dripping route of a liquid drip 4, a pair of electrodes 5a, 5b are provided, and arranged at interval sufficient for allowing the liquid drip 4 to pass through between them. A capacitance detecting circuit 6 for detecting the capacitance between the electrodes 5a, 5b is connected to a pair of electrodes 5a, 5b, and a signal converting circuit 7 for converting a capacitance signal outputted from the capacitance detecting circuit 6 to a logic signal is connected to the capacitance detecting circuit 6. Moreover, a control circuit 8 for processing a signal outputted from the signal converting circuit 7, and controlling the whole device is connected, to the signal converting circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet counter which is attached to a dispenser or the like which needs to discharge an accurate amount of liquid and which counts the liquid droplets from the discharge port.

[0002]

2. Description of the Related Art Conventionally, a droplet counter of this type is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-109271.
An optical detector, which is a combination of a light projector such as an LED and a light receiver such as a photodiode, is used for the liquid droplet detection unit.

In such a droplet counter, light is constantly projected from the light projector toward the light receiver, and when the liquid droplet passes between the respective elements of the light projector and the light receiver, the light projector projects light. The emitted light is blocked by the droplets, and the amount of light received by the light receiver decreases. Therefore, the output signal level of the light receiver changes, and the passage of the liquid drop is detected by catching the change of the output signal from the light receiver.

[0004]

However, in the droplet counter using the above optical detector in the droplet detecting section, in the case of non-transparent droplets having a large light reflectance,
Since the amount of light received by the light receiver greatly decreases and the output signal level changes greatly, it was possible to detect the passage of liquid droplets, but a transparent body with a low light reflectance, such as water. In the case of a droplet, the amount of light received by the light receiver hardly changes, and the output signal level thereof does not change, so it is difficult to detect passage of the droplet, and the number of droplets is accurately counted. There was a problem that I could not.

Further, since the optical detector is easily affected by ambient light such as sunlight or indoor light, malfunction is likely to occur, and in order to prevent such malfunction, a special operation is required in the optical section and the electric circuit section. However, there has been a problem in that the cost of the droplet counter itself is increased accordingly.

The present invention has been made in order to solve the above-mentioned problems, and an inexpensive liquid droplet counter capable of accurately counting the number of liquid droplets regardless of the type of liquid is provided. It is intended to be provided.

[0007]

In order to achieve this object, a liquid drop counter of the present invention is a liquid drop counter which drops a liquid in a liquid drop state and counts the number of liquid drops. Between the pair of electrodes, which are arranged facing each other in the dropping path with a sufficient distance for the droplets to pass therethrough, and whose capacitance changes by the passage of the droplets, and between the pair of electrodes. The liquid crystal display device includes a liquid drop detection unit that detects the liquid drops when the capacitance changes, and a liquid drop counting unit that counts the number of the liquid drops dropped by a signal from the liquid drop detection unit.

[0008]

In the droplet counter of the present invention having the above structure, a pair of electrodes, which are opposed to each other with a sufficient distance for the droplets to pass through, are placed in the dropping path of the droplets. The capacitance between the electrodes is changed by the passage of the droplet, the droplet detection means detects the droplet by the change in the capacitance,
The droplet count means counts the number of dropped droplets in response to a signal from the droplet detection means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a droplet counter embodying the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the droplet counter of this embodiment comprises a dropping device 1 having a dropping portion 3, a pair of electrodes 5a,
5b, an electrostatic capacitance detection circuit 6, a signal conversion circuit 7, a control circuit 8, an operation panel 9, and a display 10.

A measuring liquid 2 can be inserted into the inside of the dropping device 1, and the measuring liquid 2 is in a droplet state (droplet 4) from a dropping portion 3 formed of a thin tube provided in the lower portion of the dropping device 1. And then drip. A pair of electrodes 5a, 5a,
5b are provided and are arranged with sufficient spacing for the droplets 4 to pass between them. A pair of electrodes 5a,
An electrostatic capacitance detection circuit 6 that detects the electrostatic capacitance between the electrodes 5a and 5b is connected to 5b. Further, the electrostatic capacitance detection circuit 6 outputs the electrostatic capacitance detection circuit 6 to this electrostatic capacitance detection circuit 6. Signal conversion circuit 7 for converting electrostatic capacitance signals into logic signals
Are connected. A control circuit 8 that processes a signal output from the signal conversion circuit 7 and controls the entire apparatus is connected to the signal conversion circuit 7. The control circuit 8 includes an operation panel 9 for operating the apparatus and A display device 10 for displaying the number of drops and the like is connected.

The capacitance detecting circuit 6 constitutes the droplet detecting means of the present invention, and the control circuit 8 constitutes the droplet counting means.

Next, the operation of the droplet counter of this embodiment will be described with reference to FIGS.

FIGS. 2 and 3 are diagrams showing a temporal change when the dropping liquid passes between the electrodes 5a and 5b and is detected, and FIG. 4 is an output signal diagram of the electrostatic capacitance detecting circuit. . still,
(A) to (g) in FIGS. 2 and 3 correspond to a to g in FIG. 4.

When the dropping device 1 is filled with the measuring liquid 2 and the operator operates a start switch on the operation panel 9 (not shown), the measuring liquid 2 is dropped from the dropping unit 3.

As shown in FIG. 2A, the dropped droplet 4
However, in a state where it does not reach between the electrodes 5a and 5b arranged in the dropping path, the electrostatic capacitance between the electrodes 5a and 5b is determined by the dielectric constant of only air, and the output signal from the electrostatic capacitance detection circuit 6 The level is “A” as shown in the area a in FIG. 4, and since this value is smaller than the comparison value “C”, the output from the signal conversion circuit 7 is “L”.

As shown in FIG. 2B, the dropped droplet 4
Reaches between the electrodes 5a and 5b arranged in the dropping path, and further enters between the electrodes 5a and 5b.
The electrostatic capacitance between a and 5b is determined by the insertion state of the droplet 4, and the level of the output signal from the electrostatic capacitance detection circuit 6 gradually increases from "A" as shown in the area b in FIG. Two
As shown in (c), when the droplet 4 completely enters between the electrodes 5a and 5b, the level of the output signal from the electrostatic capacitance detection circuit 6 is "B" as shown in the area c in FIG. become. During this period, the level of the output signal from the electrostatic capacitance detection circuit 6 becomes higher than the comparison value “C”, so the output of the signal conversion circuit 7 changes from “L” to “H”.

As shown in FIG. 2D, the dropped droplet 4
However, when it is located between the electrodes 5a and 5b arranged in the dropping path, the level of the output signal from the electrostatic capacitance detection circuit 6 is "B" as shown in the area d in FIG. The output from the circuit 7 maintains "H".

As shown in FIG. 3 (e), the dropped droplet 4
However, as it comes out from between the electrodes 5a and 5b arranged in the dropping path, the capacitance between the electrodes 5a and 5b is determined by the insertion state of the droplet 4, and the level of the output signal from the capacitance detection circuit 6 is determined. 4 gradually decreases from “B” as shown in the area e in FIG. 4, and as shown in FIG.
When it completely comes out from between b, the level of the output signal from the electrostatic capacitance detection circuit 6 becomes "A" as shown in the area f in FIG. During this period, the electrostatic capacitance becomes smaller than the comparison value C, so the output of the signal conversion circuit 7 changes from “H” to “L”.

Next, as shown in (g) of FIG. 3, when the dropped droplet 4 is separated from the electrodes 5a and 5b, the electrostatic capacitance between the electrodes 5a and 5b depends on the dielectric constant of air only. The level of the output signal from the fixed capacitance detection circuit 6 is “A”.
Since this value is smaller than the comparison value “C”, the output from the signal conversion circuit 7 maintains “L”.

Therefore, when one droplet 4 passes between the pair of electrodes 5a, 5b arranged in the dropping path of the droplet 4, the output of the signal conversion circuit 7 is "L", "H". ,
It changes to "L". When the next droplet 4 dropped from the dropping unit 3 of the dropping device 1 also passes through the electrodes 5a and 5b, the electrostatic capacitance between the electrodes 5a and 5b is A, similarly to the above.
B and A, and the output of the signal conversion circuit 7 also changes to "L", "H", and "L".

Each time the droplet 4 passes between the electrodes 5a and 5b, the above-mentioned signal change is transmitted from the conversion circuit 7 to the control circuit 8, and the control circuit 8 changes the signal. Based on this, the number of drops 4 is counted. Control circuit 8
Displays the counted number on the display 10 after 1 minute has elapsed since the above-described droplet counting operation was performed for a certain period of time, for example, 1 minute after the start switch of the operation panel 9 (not shown) was operated. The droplet counting operation is completed.

As described above, in the droplet counter of the present embodiment, the passage of the droplet 4 is detected by the change in the electrostatic capacitance between 5a and 5b. Therefore, in the case of a transparent droplet such as water. Can also be reliably detected, and an accurate droplet count can be obtained. Further, since the device itself is simply configured, the cost of the device is relatively low.

[0024]

As is apparent from the above description, in the droplet counter of the present invention, the capacitance between the electrodes provided in the dropping path of the droplet changes, whereby the droplet detecting means is changed. Detects droplets, it is possible to accurately count the number of droplets regardless of the type of liquid. Moreover, since the device is simply configured, it can be provided at a low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a droplet counter of the present invention.

FIG. 2 is a diagram showing a temporal change in a state in which a dropping liquid is detected in the electrode of the present invention.

FIG. 3 is a diagram showing a temporal change in a state in which a dropping liquid is detected in the electrode of the present invention.

FIG. 4 is an output signal diagram of the electrostatic capacitance detection circuit of the present invention.

[Explanation of symbols]

 4 Droplet 5a Electrode 5b Electrode 6 Capacitance Detection Circuit 7 Signal Conversion Circuit 8 Control Circuit

Claims (1)

[Claims] 1. A liquid drop counter for dropping a liquid in a liquid drop state and counting the number of liquid drops, wherein a sufficient distance is provided for the liquid drops to pass through the liquid drop dropping path. And a pair of electrodes that are arranged so as to face each other and have a capacitance that changes as the droplet passes, and a droplet detection unit that detects the droplet by changing the capacitance between the pair of electrodes. And a droplet counting means for counting the number of droplets of the droplet in response to a signal from the droplet detecting means.